What is time? How did it come into existence? Is there any end of it?

The idea of the need to measure time is universal and is documented in the earliest records of ancient civilizations. The English word time comes from the Latin tempus. Time is a continuum that lacks spatial dimensions.
The challenge of defining time is compounded because such a definition seems to depend on reference to the concept that is being defined; for example, past and future have reference only to a concept of the present. In recent centuries, the concept of time has concerned philosophers and scientists. Henri Bergson, for example, posited that understanding time, or the flow of the now, is non-rational or intuitive. The idea of time as illusory is a common claim, in reference to the shifting character of the now, which constantly moves. Defining time has also been considered a problem of language; Ludwig Wittgenstein considered handling time primarily to be a linguistic problem, requiring the grasp of relations such as before and after.
For human beings, time is a flow in one direction, and as such, it is inexorably bound up with the concept of death. Preoccupation with time and terrestrial life contrasted to a possible afterlife is therefore a concern of all major religions. The idea that time may end is inseparable from the question of mortality, as for any individual, death will bring a stop to time.
https://www.britannica.com/science/time